In order to
avoid over-stimulation and overload of narrow spaces and through unwanted contact with family members and visitors.

ElaborationIn the theme of this recommendation the widely different experiences with stairs and corridors is worded as follows: Most ‘neurotypicals’ use stairs and corridors thoughtlessly, but most people on the spectrum cannot. They notice their dimensions, materials, the lighting and the sounds much stronger and experience these more readily as oppressive, painful or disquieting. Moreover, stairs and corridors are where they get lost, where they get in touch – bodily or otherwise – with others and where a number of their senses – including the sense of equilibrium – are put to the test.
From this follows a multitude of issues which should ideally be taken into account when building stairs and corridors in a new home or when choosing a home for someone on the spectrum.

The general principle of generous space standards addresses a number of these concerns. Spacious stairs and corridors lessen the arousal of negative feelings such as oppressive, painful or disquieting.
Also unintended bodily contact of visitors or roommates can more easily be avoided.
Niches and corners can provoke stress if one feels oppressively enclosed and should then be avoided or closed off.